JPS60203846A - Oxygen sensor testing circuit of air fuel ratio control device - Google Patents
Oxygen sensor testing circuit of air fuel ratio control deviceInfo
- Publication number
- JPS60203846A JPS60203846A JP59061706A JP6170684A JPS60203846A JP S60203846 A JPS60203846 A JP S60203846A JP 59061706 A JP59061706 A JP 59061706A JP 6170684 A JP6170684 A JP 6170684A JP S60203846 A JPS60203846 A JP S60203846A
- Authority
- JP
- Japan
- Prior art keywords
- oxygen sensor
- converter
- sensor
- resistor
- fuel ratio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000001301 oxygen Substances 0.000 title claims abstract description 45
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 45
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 44
- 239000000446 fuel Substances 0.000 title claims abstract description 19
- 230000006866 deterioration Effects 0.000 claims abstract description 11
- 239000003054 catalyst Substances 0.000 claims description 7
- 230000007423 decrease Effects 0.000 claims description 5
- 230000003247 decreasing effect Effects 0.000 claims description 4
- 238000007689 inspection Methods 0.000 claims description 3
- 238000011144 upstream manufacturing Methods 0.000 claims description 2
- 150000002926 oxygen Chemical class 0.000 claims 1
- 238000001514 detection method Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 230000001105 regulatory effect Effects 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/403—Cells and electrode assemblies
- G01N27/406—Cells and probes with solid electrolytes
- G01N27/4065—Circuit arrangements specially adapted therefor
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Molecular Biology (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Measuring Oxygen Concentration In Cells (AREA)
Abstract
Description
【発明の詳細な説明】
本発明は、ガス機関等の空燃比制御装置に備わる酸素セ
ンサの劣化状態を検査する検査回路に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inspection circuit for inspecting the deterioration state of an oxygen sensor provided in an air-fuel ratio control device of a gas engine or the like.
ガス機関等の空燃比制御装置は、排気管途中の三元触媒
の上流側に酸素センサを取りイ」け、該酸素センサから
の出力をフィードバックして、吸気別において吸入空気
に対し燃料供給量を増減させ、前記触媒入口での酸素濃
度が一定値に保たれるよう制御するものである。Air-fuel ratio control devices for gas engines, etc. install an oxygen sensor upstream of a three-way catalyst in the exhaust pipe, feed back the output from the oxygen sensor, and adjust the amount of fuel supplied to intake air for each intake air. is controlled so that the oxygen concentration at the catalyst inlet is maintained at a constant value.
ところで、前記空燃比制御装置に備わる酸素センサは、
高温の排気にさらされるため、その寿命は機関の寿命に
比べ著しく短かく、早期にその出力レベルが低下する。By the way, the oxygen sensor provided in the air-fuel ratio control device is
Because it is exposed to high-temperature exhaust gas, its lifespan is significantly shorter than that of the engine, and its output level drops prematurely.
この低下した出力値をそのまま読み取って自動詞ｉｌｌ
がなされると、触媒入口での酸素濃度が所定値よりも大
幅にずれる不都合な事態が生ずる。そのため酸素センサ
は適宜劣化の状態を検査し、劣化が著しければ取り換え
る必要があるが、単に酸素センサの出力値を読み取って
いるだけでは、該出力値が酸素濃度ばかりでなく排気温
度の高低により大きく変化するので、出力レベルの低下
が酸素センサの劣化によるものか、その他の要因による
ものかを明確には区別できず、従って劣化状態を判別で
きない。The intransitive verb ill is read by reading this decreased output value as it is.
If this is done, an inconvenient situation will occur in which the oxygen concentration at the catalyst inlet deviates significantly from a predetermined value. Therefore, it is necessary to inspect the oxygen sensor for deterioration as appropriate and replace it if the deterioration is significant.However, simply reading the output value of the oxygen sensor will cause the output value to vary depending not only on the oxygen concentration but also on the exhaust temperature. Since the output level varies greatly, it is not possible to clearly distinguish whether the decrease in the output level is due to deterioration of the oxygen sensor or to other factors, and therefore the state of deterioration cannot be determined.
本発明は空燃比制御装置に簡単な構成の回路を付加する
ことによって、機関運転中においても酸素センサの劣化
を検出しうるようにしたものである。The present invention makes it possible to detect deterioration of the oxygen sensor even during engine operation by adding a circuit with a simple configuration to the air-fuel ratio control device.
以下本発明の詳細を図示の一実施例に基づいて説明する
。第１図は本発明の一実施例の構成図であって、同図中
、符号１は機関の燃焼室、２は吸気管、３は排気管であ
り、吸気管２の上流部にミキサ４とスロットル弁５とが
配設されている。燃料供給管６は調圧弁７の下流側で主
供給管６ａと副供給管６ｂとに分岐し、主供給管６ａは
ミキサ４に直結しているが、副供給管６ｂは供給量調整
手段８を介してミキサ４の下流側に接続されている。供
給量調整手段８はテーパ形ニードル弁のような調整弁の
変位で燃料の流量、従って供給量を増減させるもので、
これには調整弁を変位させるステップモータのようなア
クチュエータ９が付設されている。２７は空気供給管で
ある。一方、排気管３の中途部には三元触媒１０が介装
されており、その入口側に酸素センサ１１が取り付けら
れている。１２は面記酸素センサ１１からの検出信号に
基いて供給量調整手段８のアクチュエータ９を駆動制机
する制御部であって、ＣＰ Ｕ １３、Ａ／Ｄコンバー
タ１４、入出力インターフェース１５、ＲＯＭ１６、Ｒ
ＡＭ１７等から構成されている。The details of the present invention will be explained below based on an illustrated embodiment. FIG. 1 is a block diagram of an embodiment of the present invention, in which reference numeral 1 is a combustion chamber of an engine, 2 is an intake pipe, and 3 is an exhaust pipe. and a throttle valve 5 are provided. The fuel supply pipe 6 branches into a main supply pipe 6a and a sub-supply pipe 6b on the downstream side of the pressure regulating valve 7, and the main supply pipe 6a is directly connected to the mixer 4, but the sub-supply pipe 6b is connected to the supply amount adjusting means 8. It is connected to the downstream side of mixer 4 via. The supply amount adjusting means 8 increases or decreases the fuel flow rate and therefore the supply amount by displacing a regulating valve such as a tapered needle valve.
It is equipped with an actuator 9, such as a step motor, which displaces the regulating valve. 27 is an air supply pipe. On the other hand, a three-way catalyst 10 is interposed in the middle of the exhaust pipe 3, and an oxygen sensor 11 is attached to the inlet side of the three-way catalyst 10. 12 is a control unit that drives and controls the actuator 9 of the supply amount adjusting means 8 based on the detection signal from the oxygen sensor 11, and includes a CPU 13, an A/D converter 14, an input/output interface 15, a ROM 16, R
It is composed of AM17 etc.
酸素センサ１１の信号線１８は前記Ａ／Ｄコンバータ１
４に接続され、更にこの信号線１８にはＡ／Ｄコンバー
タ１４と並列に常開のスイッチ手段１９により断続する
所定値の抵抗２０が接続されている。スイッチ手段１９
はこの例ではリレースイッチを用いているが、手動のス
イッチ、半導体スイッチ素子等、スイッチ動作をするも
のであればよい。酸素センサ１１は、第２図に示すよう
に起電力部分１１ａと内部抵抗１１ｂとから成ると考え
られるが、前記抵抗２０の抵抗値は１例としてこの酸素
センサ１１の初期状態における内部抵抗１１ｂの抵抗値
と同一に設定することができる。２１は前記スイッチ手
段１９のコイル１９ａを駆動するためのトランジスタで
、これのベースには入出力インターフェース１５から電
圧が印加されるようになっている。２２はスイッチ手段
１９のコイル１９ａの入力電源端子、２３は酸素センサ
１１のアース線、２４はＡ／Ｄコンバータ１４のアース
線である。操作部２５は制御部１２全体の動作を制御動
作から酸素センサ検査の動作に切り換えるものであり、
表示器２ＧはＡ／Ｄコンバータ１４を通じてＣＰＵ１３
が読み取ったＡ／Ｄコンバータ１４への入力値を表示す
るものである。The signal line 18 of the oxygen sensor 11 is connected to the A/D converter 1.
Further, a resistor 20 having a predetermined value is connected to the signal line 18 in parallel with the A/D converter 14, and is connected to the signal line 18 in parallel with the A/D converter 14. Switch means 19
Although a relay switch is used in this example, it may be a manual switch, a semiconductor switch element, or any other device that operates as a switch. The oxygen sensor 11 is considered to be composed of an electromotive force portion 11a and an internal resistance 11b as shown in FIG. It can be set the same as the resistance value. Reference numeral 21 denotes a transistor for driving the coil 19a of the switching means 19, and a voltage is applied to the base of this transistor from the input/output interface 15. 22 is an input power terminal of the coil 19a of the switch means 19, 23 is a ground wire of the oxygen sensor 11, and 24 is a ground wire of the A/D converter 14. The operation unit 25 switches the operation of the entire control unit 12 from a control operation to an oxygen sensor inspection operation,
The display device 2G is connected to the CPU 13 through the A/D converter 14.
The input value read by the A/D converter 14 is displayed.
次に上記構成から成る装置の動作を説明する。Next, the operation of the apparatus having the above configuration will be explained.
まず操作部２５が操作されていない時は、スイッチ手段
１９が開状態であり、酸素センサ１１の出力はすべてＡ
／Ｄコンバータ１４を通じてＣＰ Ｕ １３に入力され
る。Ｃ’Ｂ Ｕ １３においては酸素センサ１１の酸素
検出信号に基づいて燃料供給量が算出され、そわに応じ
た駆動指令信号が入出力インターフェース１５を通じて
出力され、その結果アクチュエータ９が駆動指令信号に
応動し、供給量調整手段８において燃料供給量が調整さ
れる。First, when the operation part 25 is not operated, the switch means 19 is in an open state, and the output of the oxygen sensor 11 is all A.
The signal is input to the CPU 13 through the /D converter 14. In the C'B U 13, the fuel supply amount is calculated based on the oxygen detection signal of the oxygen sensor 11, and a drive command signal corresponding to the stiffness is outputted through the input/output interface 15, and as a result, the actuator 9 responds to the drive command signal. However, the fuel supply amount is adjusted by the supply amount adjustment means 8.
しかして酸素センサ１１の検査をする場合は、操作部２
５を操作する。この操作信号は入出力インターフェース
１５を通じてＣＰ Ｕ １３に入力され、これによって
アクチュエータ９をシステムが必ずＲＩＣＨとなるポジ
ションにセットした後制御部１２全体の制御動作（酸素
検出信号に基づいて駆動指令信号を出力する動作）を中
断するとともに、その時の酸素検出信号の出力値が表示
器２６に表示する。これとともに入出力インターフェー
ス１５からトランジスタ２１のベースに電圧が印加され
るため、コイル１９ａに通電しスイッチ手段１９が閉じ
る。このため酸素センサ１１の出力はＡ／Ｄコンバータ
１４と抵抗２０とに分圧され、Ａ／Ｄコンバータ１４へ
の入力は低下する。この低下した入力値はＣＰＵ１３に
読み取られ、その値が表示器２６に表示される。Therefore, when testing the oxygen sensor 11, the operating section 2
Operate 5. This operation signal is input to the CPU 13 through the input/output interface 15, and after setting the actuator 9 to a position where the system is always at RICH, the control operation of the entire control section 12 (a drive command signal is generated based on the oxygen detection signal) is performed. At the same time, the output value of the oxygen detection signal at that time is displayed on the display 26. At the same time, a voltage is applied from the input/output interface 15 to the base of the transistor 21, so that the coil 19a is energized and the switch means 19 is closed. Therefore, the output of the oxygen sensor 11 is divided between the A/D converter 14 and the resistor 20, and the input to the A/D converter 14 is reduced. This decreased input value is read by the CPU 13, and the value is displayed on the display 26.
この場合、抵抗２０の抵抗値が、酸素センサ１１の初期
状態での内部抵抗１１ｂの値と同一に設定してあれば、
Ａ／Ｄコンバータ１４への入力は、制御動作時の２分の
１．もしくはそれ以下のレベルとなる。酸素センサ１１
の劣化は、内部抵抗値の増大となって現われるから、酸
素センサ１１が劣化している場合は、Ａ／Ｄコンバータ
１４の入力が制御動作時の値の２分の１より大幅に低下
することになる。In this case, if the resistance value of the resistor 20 is set to be the same as the value of the internal resistance 11b in the initial state of the oxygen sensor 11,
The input to the A/D converter 14 is 1/2 of the control operation. Or at a lower level. Oxygen sensor 11
Deterioration of the oxygen sensor 11 appears as an increase in internal resistance, so if the oxygen sensor 11 has deteriorated, the input to the A/D converter 14 will be significantly lower than half of the value during control operation. become.
表示器２Ｇには、制御動作時におけるＡ／Ｄコンバータ
１４への入力値と、抵抗２０が介在したのちの入力値が
表示されるから、操作者は両数値を目視確認して、その
差から酸素センサ１１の劣化を判断する。The display 2G displays the input value to the A/D converter 14 during control operation and the input value after the resistance 20 has been interposed, so the operator can visually check both values and calculate the difference between them. Determine whether the oxygen sensor 11 has deteriorated.
本発明は上述の通り、酸素センサの信号線にＡ／Ｄコン
バータと、スイッチ手段により断続する所定値の抵抗と
を並列に接続し、前記スイッチ手段が閉じられた時に低
下したＡ／Ｄコンバータへの入力値と、それ以前の制御
動作時における入力値とをそれぞれ表示器に表示するよ
うにしたもので、スイッチ手段を閉じることによって生
じるＡ／Ｄコンバータへの入力の低下分は抵抗の抵抗値
によって決まり自明であるから、スイッチ手段を閉じる
前の前記入力値と閉じた後の入力値とを表示器の表示か
ら確認し比較することによって、酸素センサの内部抵抗
値の増大、即ち酸素センサの劣化を検出することができ
る。As described above, the present invention connects an A/D converter and a resistor of a predetermined value that is intermittent by a switch means in parallel to the signal line of an oxygen sensor, and connects the A/D converter which has decreased when the switch means is closed. The input value and the input value during the previous control operation are displayed on the display respectively, and the decrease in the input to the A/D converter caused by closing the switch means is determined by the resistance value of the resistor. Since it is obvious that the input value before closing the switch means and the input value after closing the switch means can be confirmed and compared from the display on the display, an increase in the internal resistance value of the oxygen sensor, that is, an increase in the internal resistance value of the oxygen sensor can be confirmed. Deterioration can be detected.
しかも既存の空燃比の制御部を利用しこれに簡単な構成
の回路を付加するものであるから、安価に実施しうるば
かりでなく、制御部が作動している途中、即ち機関運転
中であっても、酸素センサの検査を実施することができ
る。Furthermore, since it utilizes the existing air-fuel ratio control section and adds a simple circuit to it, it is not only possible to implement it at low cost, but it can also be implemented while the control section is operating, that is, while the engine is running. Oxygen sensor testing can be carried out even if the
第１図は本発明の回路を備えたガス機関の空燃比制御装
置の構成図、第２図は酸素センサの等価回路である。
１・・・・・・燃焼室、２・・・・・・吸気管、３・・
・・・・排気管、１１・・・・・・酸素センサ、１２・
・・・・・制御部、１３・・・・・・ｃｐＵ；、１４・
・・・・・Ａ／Ｄコンバータ、Ｉ８・・・・・・信号線
、１９・・・・・・スイッチ手段、２０・・・・・・抵
抗、２５・・・・・・操作部、２６・・・・・・表示器
。FIG. 1 is a block diagram of an air-fuel ratio control device for a gas engine equipped with the circuit of the present invention, and FIG. 2 is an equivalent circuit of an oxygen sensor. 1... Combustion chamber, 2... Intake pipe, 3...
...Exhaust pipe, 11...Oxygen sensor, 12.
... control unit, 13 ... cpU;, 14.
... A/D converter, I8 ... Signal line, 19 ... Switch means, 20 ... Resistor, 25 ... Operation section, 26 ······display.
Claims (1)
け、この酸素センサからの出力をフィードバックして吸
気側で吸入空気に対する燃料供給量を増減させ、前記触
媒入口での酸素濃度が一定値に保たれるよう制御する空
燃比制御装置における酸素センサの劣化状態を検査する
回路であって、酸素センサの信号線が接続されたＡ／Ｄ
コンバータと、酸素センサの信号線に前記Ａ／Ｄコンバ
ータと並列に接続され且つ常開のスイッチ手段により断
続する所定値の抵抗と、前記スイッチ手段か閉じられた
時に前記抵抗により低下した酸素センサからＡ／Ｄコン
バータへの入力値を読み取るＣＰＵと、この低下した入
力値及び低下前の入力値とをそれぞれ表示する表示器と
を備えた空燃比制御装置の酸素センサ検査回路。) An oxygen sensor is installed on the upstream side of the catalyst in the middle of the exhaust pipe, and the output from this oxygen sensor is fed back to increase or decrease the amount of fuel supplied to the intake air on the intake side, so that the oxygen concentration at the catalyst inlet remains constant. This is an A/D circuit that inspects the deterioration state of the oxygen sensor in the air-fuel ratio control device that controls the air-fuel ratio to be maintained at
a converter, a resistor of a predetermined value connected in parallel with the A/D converter to the signal line of the oxygen sensor and intermittent by a normally open switch means, and a resistor of a predetermined value that is lowered by the resistor when the switch means is closed. An oxygen sensor inspection circuit for an air-fuel ratio control device, comprising a CPU that reads an input value to an A/D converter, and a display that displays the input value that has decreased and the input value before the decrease.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59061706A JPS60203846A (en) | 1984-03-28 | 1984-03-28 | Oxygen sensor testing circuit of air fuel ratio control device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59061706A JPS60203846A (en) | 1984-03-28 | 1984-03-28 | Oxygen sensor testing circuit of air fuel ratio control device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS60203846A true JPS60203846A (en) | 1985-10-15 |
Family
ID=13178941
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59061706A Pending JPS60203846A (en) | 1984-03-28 | 1984-03-28 | Oxygen sensor testing circuit of air fuel ratio control device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60203846A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0258543A2 (en) * | 1986-08-23 | 1988-03-09 | VDO Adolf Schindling AG | Method and circuit for recognising the readiness for service of an oxygen measuring probe |
| US6975969B2 (en) | 2000-05-10 | 2005-12-13 | Robert Bosch Gmbh | Device for error recognition in a digital signal evaluation unit |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS545789A (en) * | 1977-06-15 | 1979-01-17 | Nippon Denso Co Ltd | Inspecting apparatus of oxygen concentration detectors |
-
1984
- 1984-03-28 JP JP59061706A patent/JPS60203846A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS545789A (en) * | 1977-06-15 | 1979-01-17 | Nippon Denso Co Ltd | Inspecting apparatus of oxygen concentration detectors |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0258543A2 (en) * | 1986-08-23 | 1988-03-09 | VDO Adolf Schindling AG | Method and circuit for recognising the readiness for service of an oxygen measuring probe |
| EP0258543A3 (en) * | 1986-08-23 | 1989-01-25 | VDO Adolf Schindling AG | Method and circuit for recognising the readiness for service of an oxygen measuring probe |
| US6975969B2 (en) | 2000-05-10 | 2005-12-13 | Robert Bosch Gmbh | Device for error recognition in a digital signal evaluation unit |
| KR100769757B1 (en) * | 2000-05-10 | 2007-10-23 | 로베르트 보쉬 게엠베하 | Device for error recognition in a digital signal evaluation unit |
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